<!DOCTYPE html>
<html>
    
<head lang="en" >
    <meta charset="UTF-8">
    <script type="text/javascript">
    function startTime(){
        var today=new Date()
        var h=today.getHours()
        var m=today.getMinutes()
        var s=today.getSeconds()
        m=checkTime(m)
        s=checkTime(s)
        document.getElementById('txt').innerHTML=h+":"+m+":"+s
        t=setTimeout('startTime()',500)
    }
    function checkTime(i){
        if (i<10){
            i="0"+i
        }
        return i
    }
    </script>
</head>
<body onload="startTime()">
    <div id="txt"></div>
    
</body>

</html>